NBER Working Papers and Publications

We show that kidney exchange markets suffer from traditional market failures that can be fixed to increase transplants by 25%-55%. First, we document that the market is fragmented and inefficient: most transplants are arranged by hospitals instead of national platforms. Second, we propose a model to show two sources of inefficiency: hospitals do not internalize their patients’ benefits from exchange, and current mechanisms sub-optimally reward hospitals for submitting patients and donors. Third, we estimate a production function and show that individual hospitals operate below efficient scale. Eliminating this inefficiency requires a combined approach using new mechanisms and solving agency problems.

Criteria for evaluating school choice mechanisms are first, whether truth-telling is sometimes punished and second, how efficient the match is. With common knowledge preferences, Deferred Acceptance (DA) dominates the Boston mechanism by the first criterion and is ambiguously ranked by the second. Our laboratory experiments confirm this. A new ex ante perspective, where preferences are private information, introduces new efficiency costs borne by strategy-proof mechanisms, like DA. In a symmetric environment, truth-telling can be an equilibrium under Boston, and Boston can first-order stochastically dominate DA in terms of efficiency, both in theory and in the laboratory.